The present invention is directed toward the art of mechanical fasteners and, more particularly, to an improved fastener component for push-on connection to a threaded stud.
The invention is especially suited for forming fasteners of the type used in the automotive industry for connecting fuel line clamps and various other components to threaded or contoured studs that are welded to the vehicle body or frame. While the invention will be described with reference to its use for the noted purposes, it should be appreciated that the invention is capable of broader applicaton and could be used in a variety of industries for many different purposes.
There has recently been developed a fastening system which has found fairly widespread use in the automotive industry. The system includes a small, male stud member having a threaded or contoured exterior and a mating female component, generally plastic, which can be axially pushed onto the stud member. Typically, the studs are joined to the vehicle frame or body components by a standard stud welding operation.
The desired relationship between the stud and the female member is preferably such that they can be axially pushed together under fairly low force but separated only with substantial reverse axial force or by an unthreading operation like a standard threaded nut.
A variety of different stud thread or exterior contours, as well as many different internal designs for the female component have been proposed in an attempt to provide the desired easy push-on, difficult to separate connection. There has, however, been little success in achieving this desired result. Typically, there has tended to be a direct relationship between the force required to connect components and the force required to separate, i.e., making the components more difficult to separate has generally been achieved only by making them significantly more difficult to join.
Fastener systems of the general type described are shown, for example, in West German Pat. No. 3,002,031. In this patent the female aperture of the connector is provided with longitudinally positioned ribs which protrude radially into the interior. Increasing the size or thickness of the ribs to increase the interference between the ribs and the threaded stud can increase the force required for separation but produces corresponding increases in the force required for axial joining. In addition, there are practical limits that can be achieved with this design since permanent deformation of the ribs and even the exterior of the female connecting component will result at some predetermined level of interference.
The purpose of the subject invention is to provide a fastening component of the type described which can be applied to a threaded or profiled bolt with a comparatively low force axial push, but which can be removed only with the application of substantially greater force or by a normal unthreading operation. In addition, a significant increase in the force required for removal or separation is achieved without any increase in the application force and without permanent deformation of the interior or exterior of the component.